Certain surgical treatments require the modification or removal of blood veins from the body. For example, the treatment of varicose veins sometimes requires the varicose veins to be removed from the body in an invasive, painful, slow-healing, and time-consuming procedure. Also, the saphenous vein is surgically modified during a procedure, known as in situ saphenous vein bypass, for alleviating conditions caused by reduced blood flow through an occluded femoral artery.
In situ saphenous vein bypass is a procedure in which the saphenous vein in a human leg, which normally returns venous blood from the ankle upwardly through the leg, is anastomosed to the femoral artery at an upstream (proximal) location on the artery and a downstream (distal) location on the artery to assume the function of the femoral artery, i.e., to deliver arterial blood to the leg. Such a bypass procedure may be required when the femoral artery has become too occluded or otherwise impaired between the upstream and downstream locations to transport the flow of blood required of it.
When the saphenous vein is to assume the function of the femoral artery, it becomes necessary to close off, i.e., to ligate, so-called "side branch" blood veins. These side branch veins are generally smaller than the saphenous vein and are colloquially known as "tributaries" when they lead to the saphenous vein and "perforators" when they lead to deeper venous circulation. Side branches ordinarily establish pathways for venous blood into the saphenous vein for returning the blood to the heart and lungs. Accordingly, to prevent the unwanted flow of arterial blood directly into the venous system via the saphenous vein, the side branches and perforators must be ligated. Stated differently, by ligating the side branches, arterial blood which is permitted to flow through the saphenous vein and thereby bypass the occluded segment of the artery is prevented from invading the venous system through the side branches.
Typically, side branches are ligated by constricting the side branches with sutures. Unfortunately, ligating side branches with sutures can be time-consuming and labor-intensive, because all the side branches must be located either by making a large number of small incisions in the leg or by making one very large incision. Also, it is difficult to ligate side branches with sutures in less-invasive procedures, i.e., endoscopically.
As recognized by the present invention, side branches of the saphenous vein may be ligated in less invasive procedures. More particularly, the present invention recognizes that blood flow through side branches of the saphenous vein can be quickly and easily stopped by advancing an electrode into the side branch and energizing the electrode to cause the tissue to coagulate and thereby block fluid flow through the side branch. As further recognized by the present invention, varicose veins can be quickly and easily treated by ligating them in less invasive procedures. Thereby, unsightly discolorations in the leg attributable to varicose veins can be eliminated in an out-patient procedure.
Although coagulating devices have been introduced for other surgical applications, these devices typically have bulky components which are designed for use within a relatively large body cavity that has been exposed by surgery. Consequently, existing coagulating devices cannot easily be used to stop blood flow from "hard-to-reach" sources, such as saphenous vein side branches. Furthermore, existing coagulating devices cannot easily be used in less-invasive surgery for the treatment of varicose veins.
Moreover, many coagulating devices function simply by applying electricity to tissue. The length of time the tissue is exposed to the electricity is controlled by the surgeon, usually by depressing a foot pedal linked to a source of electricity, e.g., a Bovie model generator made by Valley Labs of Colorado. Consequently, tissue can easily be unintentionally overheated, thereby causing unwanted scabbing, charring, and other unnecessary tissue damage. Such damage can be particularly onerous in certain circumstances, e.g., saphenous vein side branch ligation and varicose vein treatment. Indeed, excessive electro-ligation of varicose veins in an attempt to reduce discoloration caused by the veins may be a cure that is worse than the disease. Stated differently, applying rf energy to a blood vein over excessive time periods or at excessively high power can result in arcing and perforation of vein.
It is therefore an object of the present invention to provide a device that can less-invasively ligate side branches of a saphenous vein. Another object of the present invention is to provide an apparatus and method for less invasive treatment of varicose veins. Still another object of the present invention is to provide an apparatus and method for less invasive surgical ligation which is easy to use and cost-effective to manufacture.